A variable pitch propeller is a propeller capable of being rotated about its longitudinal axis to vary the blade pitch. In aviation applications, a variable pitch propeller may be used to control the pitch of a propeller blade as it rotates, as in helicopter rotors, e.g., to control direction of flight, increase efficiency, and/or the amount of thrust (or lift) generated.
Typically, the pitch of a variable pitch propeller is controlled by a mechanical linkage and/or hydraulics. A control system typically is used to control the elements that vary the pitch. Such mechanisms may be complicated and may require frequent maintenance from highly skilled technicians. In addition, the mechanisms add weight, which results in higher fuel costs, or shorter battery life and therefore flight time in the case of an electric motor driven rotor, and which may make such propellers impractical for applications in which the additional weight is prohibitive.